Mark McCormack, an agent and manager who transformed the world of sports by turning top athletes such as Arnold Palmer into marketable stars, died yesterday at age 72.

Mr. McCormack died in a New York hospital four months after cardiac arrest left him in a coma, his Cleveland-based company said.

Mr. McCormack's company, IMG, grew into an international business powerhouse representing the likes of Tiger Woods, Joe Montana and Derek Jeter. His empire began with a handshake agreement with Palmer in 1960.

"I have lost one of my closest friends, and the world of sports and entertainment has lost one of its great giants," Palmer said. "I never had a moment's regret or misgiving about placing much of the guidance of my future in his hands, and it certainly proved to be the right thing for both of us."

Mr. McCormack's success with Palmer set the way for Woods to become one of the most recognizable faces on the planet before he was in his mid-20s. While still a teenager, Woods first met Mr. McCormack during a practice round for the U.S. Open.

"He was a genius when it comes to sports marketing," Woods said yesterday. "If it wasn't for him, obviously we wouldn't be in the position we are right now."

Mr. McCormack was selected as one of the 10 most powerful people in sports last December by The Sporting News. In 1990, Sports Illustrated described McCormack as "the most powerful man in sports."

He was a lawyer with the Cleveland firm Arter & Hadden when he signed Palmer, enabling him to combine his expertise in law and business with his passion for golf.

Mr. McCormack had learned the game playing with his father and poet Carl Sandburg, who was also his godfather. After playing on the college team at William and Mary team, Mr. McCormack qualified for the U.S. Open and several U.S. and British amateur tournaments.

As chairman and chief executive officer, McCormack transformed International Management Group into a sports and entertainment complex of businesses simply known as IMG. It has 80 offices in 32 countries and employs more than 2,000 people.

Mr. McCormack's personal philosophy was, "Be the best, learn the business and expand by applying what you already know."

IMG's client list includes the Royal & Ancient Golf Club of St. Andrews, the Nobel Foundation, the Kennedy Space Center and the Smithsonian Institution. Mr. McCormack even handled projects for global leaders such as Margaret Thatcher, Mikhail Gorbachev and the pope.

"Mark perhaps had a greater impact on the game of golf, from a business perspective, than anybody in its history," said Jack Nicklaus, who signed with IMG when he turned pro in 1962 and recently rejoined the agency.

"He made golf a business. Then, you look at all the other areas and arenas he entered, and you see that he made managing people a business -- a viable business. He truly was an innovator."